It has been a long tradition that highly skilled perfumers carefully select fragrance materials to blend into a composition with the goal of achieving an overall specific fragrance profile of strength and character. In so doing, they need to bear in mind differences in the individual character and volatility of the fragrance materials that are the components of the full fragrance. Conventional perfuming compositions have fragrance profile characterized by a high amount of the low volatile fragrance materials and lower amounts of the volatile fragrance materials. The low volatile fragrance materials are known as “base notes”, while the volatile fragrance materials can be further divided into high volatile fragrance materials, identified as “top or head notes”, and medium or moderate volatile fragrance materials, identified as “middle or heart notes”. Perfumers typically classify fragrance materials as a base, heart or top note according to their specific characters. Unfortunately, there is no universal convention because this type of classification scheme tends to be subjective.
The top notes tend to smell citrusy, green, light, fresh, and comprise typically from about 0.1 wt % to 40 wt % relative to the total weight of the perfume formulation. Typically, perfumers use top notes to deliver the initial impression of the composition but do not rely on them to contribute much to its overall fragrance profile over time after application.
Middle or heart notes are associated with floral characters (e.g., jasmin, rose), fruity, marine, aromatic or spicy characters and make up from about 0.1 wt % to about 60 wt % relative to the total weight of the perfume formulation. Generally, they become dominant to the untrained nose from several minutes after application and can last up to a few hours afterwards.
Base or bottom notes are characterized as animalic, woody, sweet, amber or musky and can exist at greater than 30 wt % relative to the total weight of the perfume formulation. Typically, they are not perceived as dominant until several hours after the application of the perfume or during “dry-down”. Base notes are relied upon at high levels to improve the strength of the overall fragrance profile over time and replace the heart notes when these are declining. The consequence of using base notes at high levels is that they impart particular odour characters, such as for example, musky, woody, ambery, warm and sweet, which overpower and dominate the fragrance character over time. Some of these base notes have become such common materials (e.g., ethylene brassylate, Galaxolide®, etc.) that many fragrance dry-downs appear repetitive, boring, non-memorable and un-interesting to consumers. However, if base notes are reduced or excluded then the fragrance strength weakens over time and does not last for a sufficient duration.
One problem with the above classification approach is that due to the somewhat subjective nature of characters, there is inconsistency with the construction of fragrance compositions. Another problem is that consumers tend to complain that middle notes tend to fade too quickly after application of the composition and that the character of the middle notes are undesirably altered by the presence of large amounts of the base notes during the period known as the “dry-down” phase.
Thus, it is desirable to provide new rules for objectively classifying fragrance materials according to their volatility using their vapor pressures defined at a suitable temperature, instead of their characters. The new rules operate irrespective of the perfumers performing the classification. In particular, the new rules classify the fragrance materials into low volatile fragrance materials or volatile fragrance materials for formulating into fragrance mixtures. It is further desirable to have a composition which retains a significant portion of its initial fragrance profile over time, hence, the floral, fruity, aromatic or spicy characters attributable to the volatile fragrance materials are perceived for many hours after application. It is also desirable that the fragrance profile of the composition remains noticeable to the consumer over longer periods of time. It is further desirable to be able to create new to the world fragrance profiles wherein one, or several, well-recognized volatile fragrance materials characters, are maintained over time.
It is therefore a challenge to formulate a composition having improved longevity of the fragrance profile, preferably characters attributable to the volatile fragrance materials, without having the fragrance profile substantially altered over time by the presence of the low volatile fragrance materials in the composition. One approach for addressing the challenge has been to formulate with higher proportions of perfume raw materials with a low volatility and which are therefore more substantive on the substrate. However, as discussed above, this restricts the type of fragrance profile that can be achieved over time.
Previous attempts to overcome these problems have been through the use of various “fixatives” or “modulators” to retard the evaporation of the more volatile fragrance ingredients present in fragrance compositions. For instance, U.S. Pat. No. 4,313,855 (Dragoco) describes the use in cosmetic compositions of 1-(2,6,6-trimethylcyclohexyl)-hexane-3-ol as an odourless fixative for increasing the perfume's intensity. U.S. Pat. No. 6,147,049 (Givaudan) discloses a perfume fixative derived from tera-hydronaphthalenese for use in a wide range of fragrance compositions. U.S. Pat. No. 6,440,400B1 (Takasago Perfumery) describes a composition using trimethylcyclohexane derivatives as perfuming-holding agents and melanin-formation inhibitors. U.S. Pat. No. 6,737,396B2 (Firmenich) describes a perfume composition formed by mixing 2-30%, relative to the weight of the composition, of a fixative, (1-ethoxyethoxy)cyclododecane, to fix or exalt the musky or aromatic-type notes. U.S. Pat. No. 7,538,081 (Takasago Perfumery) approaches the same problem of fixing a perfume and/or extending the perfume release from a fragrance composition. More particularly, said document describes the use of L-menthoxy ether derivatives as fixatives in fragrance compositions comprising at least one note selected from: floral, citrus, fruity, green, mint, herb and marine. JP Patent No. 61-083114 (Kanebo) describes ether derivatives as aroma-preserving agent for fine perfume composition. JP Patent No. 61-063612 (Kanebo) discloses diethylene glycol ether derivatives as fragrance adjusting agent showing effects as a fixative and a solubilizer. JP Patent No. 62-084010 (Shiseido) describes hydroquinone glycoside as perfume fixatives applicable for all kinds of perfume and blended perfume. On the other hand, PCT Publication No. WO85/04803 (Diagnostica) describes the use of hyaluronic acid/hyaluronate as fixatives (via molecular encapsulation) in fragrance products to improve persistence of the fragrance.
There are at least one of several drawbacks to the above described use of fixatives or modulators in fragrance compositions. Firstly, these attempts, while disclosing compositions that retain the perfume by way of fixatives or modulators, do not teach the substantive reduction in the levels of low volatile fragrance materials in the fragrance compositions or the particular type of fragrance materials to include for delivering the benefits of improved fidelity and.or longevity of the fragrance profile, preferably the characters attributable from the volatile fragrance materials. Secondly, the use of fixatives or modulators in these attempts mostly shows effects on single perfume raw materials (“PRMs”), which are often not observed in a fragrance composition of a mixture of fragrance materials where a number of such fragrance materials are competing with each other to interact with said fixative or modulator. They do not teach how to formulate with fixatives or modulators in mixtures, which is not trivial. On the other hand, for other attempts that do describe mixtures, they have different fragrance design criteria and are directed to specific preferred fixative materials or modulators.
As such the previous attempts still have limitations, and do not adequately teach how to provide a composition wherein the prolonged fragrance profile, preferably the characters attributable to the volatile fragrance materials, are noticeable over time, preferably very long durations of time. Therefore, there remains a need for a composition that is perceived by the consumer over long, preferably very long, duration after application. There is also a need for a composition wherein the characters attributable to the volatile fragrance materials remains significantly consistent from its initial impression to the end. It is desirable that the compositions are relevant to fragrances derived from volatile fragrance materials having a vapor pressure greater than 0.001 Torr (0.000133 kPa) at 25° C.